我有一个方法,它通过日期对象返回ResultSet查询的值。问题是,在我的输出中,它只返回特定列中的最后一个值。我该怎么做?
public Date getTime(){
Date date = null;
DateFormat format;
try {
Class.forName("com.mysql.jdbc.Driver");
Connection con = DriverManager.getConnection(url, "root", "");
Statement stmt = con.createStatement();
ResultSet result = stmt.executeQuery("SELECT * FROM error_log WHERE service_source = 'Billbox' ");
while (result.next()) { //retrieve data
String ds = result.getString("error_date");
format = new SimpleDateFormat("M/d/yyyy H:m:s a");
date = (Date)format.parse(ds);
}
con.close();
} catch (Exception ex) {
Logger.getLogger(LogDB.class.getName()).log(
Level.SEVERE, null, ex);
}
return date;
}
然后在我的主要方法:
public static void main(String args[]){
TestA ea = new TestA();
Date ss = ea.getTime();
System.out.println(ss);
}
但这只返回查询中的最后一个值。我怎么能把其他的(旧的)打印出来呢?
您需要从查询结果中填写日期列表。试试这个:
public List<Date> getTime(){
List<Date> dates = new ArrayList<Date>();
DateFormat format;
try {
Class.forName("com.mysql.jdbc.Driver");
Connection con = DriverManager.getConnection(url, "root", "");
Statement stmt = con.createStatement();
ResultSet result = stmt.executeQuery("SELECT * FROM error_log WHERE service_source = 'Billbox' ");
while (result.next()) { //retrieve data
String ds = result.getString("error_date");
format = new SimpleDateFormat("M/d/yyyy H:m:s a");
dates.add((Date)format.parse(ds));
}
con.close();
} catch (Exception ex) {
Logger.getLogger(LogDB.class.getName()).log(
Level.SEVERE, null, ex);
}
return dates;
}
由于while循环,您可以指定最后一个值的日期。将您的方法更改为
public List<Date> getTime(){
你可以试试
List<Date> dates = new ArrayList<Date>();
然后进入while循环;
while (result.next()) { //retrieve data
String ds = result.getString("error_date");
format = new SimpleDateFormat("M/d/yyyy H:m:s a");
date = (Date)format.parse(ds);
dates.put(date);
}
return dates;
just:
List<Date> lDateDb = new ArrayList<Date>();
while (result.next()) { //retrieve data
String ds = result.getString("error_date");
format = new SimpleDateFormat("M/d/yyyy H:m:s a");
date = (Date)format.parse(ds);
lDateDb.add(date);
}
return lDateDb;
将getTime
的返回类型更改为List<Date>
,并将main更改为:
public static void main(String args[]){
TestA ea = new TestA();
List<Date> lAllDate = ea.getTime();
for (Date lDate : lAllDate)
System.out.println(lDate );
}